<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .box1 {
      width: 600px;
      height: 200px;
      background: linear-gradient(to right, red 33.333%, green 33.33%, green 66.66%, blue 66.66%);
    }

    .box2 {
      width: 600px;
      height: 200px;
      background: radial-gradient(circle farthest-side, red, green, blue, pink) ;
    }
  </style>
</head>

<body>
  <div class="box1"></div>
  <div class="box2"></div>
</body>

</html>